Some Machining Shizzle

[kitatit]

Thanks Andy. This one can tap at 2000rpm. I think 800rpm sounds a little less hair raising so ill start there.

Cheers
Kit

mine was second hand and 30 years old.

the bearing had gone and a few springs etc...

the tapping head is very strong, but just take your time and make sure you get the coding perfect. mine can run at 3000rpm but I run it at like 800rpm. even at that slow speed it can still tap holes in seconds



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that was a feed rate of 80 chop

[andy_con]

Small taps aren't that strong I've found so a nice slow and controlled speed worked well for me

At 800rpm it taps 16 holes 10mm deep in 2mins flat

[laserlackey]

This one can tap at 2000rpm. I think 800rpm sounds a little less hair raising so ill start there.

Tapping speed is mostly going to be determined by how much coolant you have in the hole. Tapping at anything over 1k RPM is ill-advised unless you have liquid flood coolant. Simply putting a little oil in the holes before you start the tapping cycle will only get you so far.

The annoying thing about tapping heads is if you're using a cutting tap ('regular' style tap) you can't do chip break cycles, so tapping long holes isn't advised. There are two types of taps that will get more efficiency out of your tapping head: one is a standard cut tap that has small channels cut into the flutes which break the chips once they reach a certain length, which helps chip evacuation out of the hole and ensures you never have chips longer than a certain length. You can even grind your own flute reliefs if you have a diamond wheel. The second is form taps. Instead of cutting material away, they deform the material along the hole wall into threads (NOTE: you need to drill a larger diameter hole for form taps. They come with their own tap drill size chart). They not only make stronger, more rigid threads (which is good for lenses since they'll fit tighter), but you can tap much faster with them with less chance of binding (and breaking) the tap on a stray chip. We routinely form tap 0-80 holes at 5k RPM here in my shop, but we have flood coolant.

Cheers!

[andy_con]

I have coolant flood but I don't use it when tapping, I put lots if oil in each hole. Nit had any issues, also I use a spiral flute tap

[laserlackey]

I have coolant flood but I don't use it when tapping, I put lots if oil in each hole. Nit had any issues, also I use a spiral flute tap

Spiral flute is the way to go. Glad you're not having any issues. I guess when you're doing only a dozen or so holes it's not so bad to oil the holes. I loathe the thought of ever going back to not using flood coolant anymore.

[The_Doctor]

Regarding tapping i have had great luck finding a working solution.
Now hear me out as it sound a bit odd but works great.
So i have a very cheap 40$ HF drill press, Very weak motor.
Position the work under the bit not under power then turn on and hold the part. (this is better for larger things vice smaller harder to hold but dont bolt the vice down)
If you set it to the slowest speed loosen the belt a bit and throw a tap in it and pull down while going threw work no problem.
If you use enough lube it can go threw in one pass but if you do it dry or have a cheap tap it will slip on the belt half way threw and then u just switch it off then manually turn it reverse then go back forward.

That's pretty much how I do it. No power though, I just run the drive belt by hand, the inertia in the system makes it run smooth. I always use a fluteless tap. I think they're chrome vanadium with some kind of 'flashing' on them to make a hard surface. They need exact drill sizes prior, and even that varies according to depth or choice of metal but it works for me. It cold-forms the thread so it's tough, and very finely surfaced. I have one 3mm tap, and one 4mm tap. I have never needed another size in the 20 years I have done this (it helps that most stuff I do is small enough not to need it), and I have never broken a tap.

I've never had a CNC mill but if they can have enough control of vertical position changing as the thread is formed, this could be fast. As it is, I can sink a 3mm thread to 16 mm in a few seconds with no risk, I just have to not do it if I'm tired and stupid.. The method works well in aluminium of any grade I've tried, and in brass and copper and mild steel and acetal plastic. Stainless steel too, just slower to do. I use a drip of 3-in-1 oil if the hole is deeper than 5mm, especially if it's a blind hole.

[andy_con]

I use flood for cutting Just not tapping

[andy_con]

One thing I forgot to mention with setting the z, if your hole is 10mm deep when using the tapmatic don't goo to 10mm. On mine once the z stops going down and starts going back up the tap travels a further 3mm. The clutch needs to engage and change to reverse

[andy_con]

New toy collected today starmill with three station tool changer

[lloyd33]

Looks like a short HeNe tube holder to me.